The invention relates to electro-optical devices whose electromagnetic radiation absorption characteristics can be selectively altered by influence of a suitably controlled electric field. More particularly, the invention is concerned with an electro-optical device for displaying animated pictorial information and alpha numeric information. It particularly relates to an electro-optical device exhibiting a phenomenon known as electrochromism in which separate discrete display segments are operated and arranged in a unitary structure with common electrolyte and counter-electrode elements.
In commonly assigned, copending U.S. application, Ser. Nos. 41,153; 41,154; and 41,155, all filed May 25, 1970, Ser. No. 41,153, abandoned and refiled as Ser. No. 211,857, Dec. 23, 1971, abandoned and refiled as Ser. No. 361,760, May 18, 1973, now U.S. Pat. No. 3,879,108; Ser. No. 41,154, abandoned and refiled as Ser. No. 609,251, Apr. 13, 1973, now pending; Ser. No. 41,155, now U.S. Pat. No. 3,708,220; and U.S. Pat. Nos. 3,521,941 and 3,578,843, there are described electro-optical devices exhibiting a phenomenon known as persistent electrochromism wherein electromagnetic radiation absorption characteristic of a persistent electrochromic material is altered under the influence of an electric field. Such devices were employed in sandwich arrangement between two electrodes. Coloration was induced by charging the electrochromic film negative with respect to the counter-electrode, employing an external potential. The counter-electrode can be the same as the persistent electrochromic material or different.
By reversing the original polarity of the field or by applying a new field, it was also possible to cancel, erase or bleach the visible coloration.
These steps of color induction and erasure are defined as cycling.
In order to display changing information, prior art arrangements have employed series of separate electrochromic display units or a moving "color front" On a single electrochromic unit.
It is an object of this invention to provide an electrochromic imaging device providing for the operation of separate electrochromic elements within a single electrochromic display in which the counter-electrode and electrolyte spacing layer are common to all the electrochromic elements.